1. Field of the Invention
The present invention relates to a planar thin-film magnetic head and a manufacturing method therefor.
2. Description of the Related Art
In recent years, a reduction in size and an increase in capacity of a magnetic disk drive as a kind of external storage device for a computer have been desired. In response thereto, the flying height of a magnetic head slider from a magnetic disk surface in recording and reproducing information is increasingly reduced, and the magnetic head slider is required to ensure stability and reliability at a low flying height and is also required to have a reduced weight.
In general, a magnetic head slider used in a magnetic disk drive has a structure such that a vertical-structure type thin-film magnetic head is located on an rear end surface (air outlet end surface) of the slider perpendicular to a flying surface (medium opposing surface) of the slider. As a result, the height (thickness) of the slider is necessarily increased by the height of the vertically located thin-film magnetic head, and it is therefore greatly difficult to realize a compact, light magnetic head slider. To cope with this, there has been proposed a planar thin-film magnetic head slider having a thin-film magnetic head horizontally located on the medium opposing surface to thereby reduce the height of the magnetic head slider.
FIG. 1 shows a schematic structure of a conventional planar thin-film magnetic head proposed in Japanese Patent Laid-open Nos. 3-127308 and 6-4829, for example. Referring to FIG. 1, a gap 10 for generating a signal magnetic field in a recording medium 16 is defined in a lower magnetic pole 2. The lower magnetic pole 2 is connected to an upper magnetic pole 4 by a pair of back closures 6 and 8, thus being magnetically closed.
A pair of spiral coils 12 and 14 for generating a signal magnetic field are located about the back closures 6 and 8, respectively. As shown in FIG. 1, the gap 10 in the conventional planar thin-film magnetic head is normal to the recording medium 16.
In the conventional planar thin-film magnetic head, the spiral coils 12 and 14 are located so that the back closures 6 and 8 become the centers of the coils 12 and 14, respectively. Accordingly, the sectional area of each back closure is limited by the area of a central portion of each coil, so that it is impossible to ensure a large sectional area of each back closure. As a result, the magnetic resistance of the back closures 6 and 8 is increased to cause a decrease in strength of the signal magnetic field at the back closures 6 and 8. Further, since the gap in the conventional planar thin-film magnetic head is normal to the recording medium, it is difficult to form a gap having a narrow width (0.3 .mu.m or less).